For those users who live backwards in time, here is information about
downgrading to Emacs version 19. We hope you will enjoy the greater
simplicity that results from the absence of certain Emacs 20 features.

The multibyte character support has been eliminated entirely. (Some
users consider this a tremendous improvement.) Each character takes up
one position in a buffer or string, and character codes are limited to
the range 0 through 255.

Fontsets, coding systems and input methods have been eliminated as well.

The mode line normally displays the string `Emacs', in case you
forget what editor you are using.

Scroll bars always appear on the right-hand side of the window.
This clearly separates them from the text in the window.

The M-x customize feature has been replaced with a very simple
feature, M-x edit-options. This shows you all the user
options right from the start, so you don't have to hunt for the ones you
want. It also provides a few commands, such as s and x, to
set a user option.

The DELETE key does nothing special in Emacs 19 when you use it
after selecting a region with the mouse. It does exactly the same thing
in that situation as it does at all other times: delete one character
backwards.

C-x C-w no longer changes the major mode according to the new file
name. If you want to change the mode, use M-x normal-mode.

In Transient Mark mode, each window displays highlighting for the region
as it exists in that window.

Outline mode doesn't use overlay properties; instead, it hides a line by
converting the preceding newline into code 015. Magically, however, if
you save the file, the 015 character appears in the file as a newline.

There is now a clever way you can activate the minibuffer recursively
even if enable-recursive-minibuffers is nil. All you have
to do is switch windows to a non-minibuffer window, and then use a
minibuffer command. You can pile up any number of minibuffer levels
this way, but M-x top-level will get you out of all of them.

We have removed the limit on the length of minibuffer history lists;
they now contain all the minibuffer arguments you have used since the
beginning of the session.

Dynamic abbrev expansion now handles case conversion in a very simple
and straightforward way. If you have requested preserving case, it
always converts the entire expansion to the case pattern of the abbrev
that you have typed in.

The compose-mail command does not exist; C-x m now
runs mail directly.

There is no way to quote a file name with special characters in it.
What you see is what you get: if the name looks remote, it is remote.

M-x grep-find has been eliminated, because grep has never
been lost.

Some Dired commands have been rearranged: two-character sequences
have been replaced with quick single-character commands:

For dired-mark-executables, type *.

For dired-mark-directories, type /.

For dired-mark-symlinks, type @.

For dired-change-marks, type c.

For dired-unmark-all-files, type C-M-?.

For dired-unmark-all-marks, type C-M-? RET.

But if you want to use dired-flag-garbage-files, &, you'll
just have to stop living in the past.

In C mode, you can now specify your preferred style for block comments.
If you want to use the style

/*
blah
blah
*/

then you should set the variable c-block-comments-indent-p to
t.

To customize faces used by Font Lock mode, use the variable
font-lock-face-attributes. See its documentation string for
details.

For efficiency, Font Lock mode now uses by default the minimum supported
level of decoration for the selected major mode.

If you kill a buffer, any registers holding saved positions in that
buffer are changed to point into limbo.

The function set-frame-font has been renamed to
set-default-font.

The variable tex-main-file doesn't exist. Of course, you can
create the variable by setting it, but that won't do anything special.

The scroll-preserve-screen-position variable has been eliminated;
and so has the feature that it controls.

We have eliminated the functions add-untranslated-filesystem and
remove-untranslated-filesystem, and replaced them with a simpler
function, using-unix-filesystems.

To keep up with decreasing computer memory capacity, many other
functions and files have been eliminated in Emacs 19. There's no need
to mention them all here. If you try to use one of them, you'll get an
error message to tell you that it is undefined or unbound.